Author: stefanct
Date: Sat Dec 29 16:04:05 2012
New Revision: 1635
URL: http://flashrom.org/trac/flashrom/changeset/1635
Log:
Add a generic SPI block unprotect function.
This does not only remove a huge pile of duplicate code, it does
also fix a bug in spi_disable_blockprotect_at25df(), which is also
a good example why duplicated code is a bad idea.
Signed-off-by: Stefan Tauner <stefan.tauner at student.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner at student.tuwien.ac.at>
Modified:
trunk/spi25_statusreg.c
Modified: trunk/spi25_statusreg.c
==============================================================================
--- trunk/spi25_statusreg.c Sat Dec 29 16:03:51 2012 (r1634)
+++ trunk/spi25_statusreg.c Sat Dec 29 16:04:05 2012 (r1635)
@@ -123,35 +123,61 @@
return readarr[0];
}
-/* A generic brute-force block protection disable works like this:
- * Write 0x00 to the status register. Check if any locks are still set (that
- * part is chip specific). Repeat once.
+/* A generic block protection disable.
+ * Tests if a protection is enabled with the block protection mask (bp_mask) and returns success otherwise.
+ * Tests if the register bits are locked with the lock_mask (lock_mask).
+ * Tests if a hardware protection is active (i.e. low) with the write protection mask (wp_mask) and bails out
+ * in that case.
+ * Finally tries to disable engaged protections and checks if any locks are still set.
*/
-int spi_disable_blockprotect(struct flashctx *flash)
+static int spi_disable_blockprotect_generic(struct flashctx *flash, uint8_t bp_mask, uint8_t lock_mask, uint8_t wp_mask)
{
uint8_t status;
int result;
status = spi_read_status_register(flash);
- /* If block protection is disabled, stop here. */
- if ((status & 0x3c) == 0)
+ if ((status & bp_mask) == 0) {
+ msg_cdbg2("Block protection is disabled.\n");
return 0;
+ }
msg_cdbg("Some block protection in effect, disabling... ");
- result = spi_write_status_register(flash, status & ~0x3c);
+ if ((status & lock_mask) != 0) {
+ msg_cdbg("\n\tNeed to disable the register lock first... ");
+ if (wp_mask != 0 && (status & wp_mask) == 0) {
+ msg_cerr("Hardware protection is active, disabling write protection is impossible.\n");
+ return 1;
+ }
+ /* All bits except the register lock bit (often called SPRL, SRWD, WPEN) are readonly. */
+ result = spi_write_status_register(flash, status & ~lock_mask);
+ if (result) {
+ msg_cerr("spi_write_status_register failed.\n");
+ return result;
+ }
+ msg_cdbg("done.\n");
+ }
+ /* Global unprotect. Make sure to mask the register lock bit as well. */
+ result = spi_write_status_register(flash, status & ~(bp_mask | lock_mask));
if (result) {
msg_cerr("spi_write_status_register failed.\n");
return result;
}
status = spi_read_status_register(flash);
- if ((status & 0x3c) != 0) {
+ if ((status & bp_mask) != 0) {
msg_cerr("Block protection could not be disabled!\n");
return 1;
}
- msg_cdbg("done.\n");
+ msg_cdbg("disabled.\n");
return 0;
}
+/* A common block protection disable that tries to unset the status register bits masked by 0x3C. */
+int spi_disable_blockprotect(struct flashctx *flash)
+{
+ return spi_disable_blockprotect_generic(flash, 0x3C, 0, 0);
+}
+
+
static void spi_prettyprint_status_register_hex(uint8_t status)
{
msg_cdbg("Chip status register is 0x%02x.\n", status);
@@ -414,43 +440,7 @@
int spi_disable_blockprotect_at25df(struct flashctx *flash)
{
- uint8_t status;
- int result;
-
- status = spi_read_status_register(flash);
- /* If block protection is disabled, stop here. */
- if ((status & (3 << 2)) == 0)
- return 0;
-
- msg_cdbg("Some block protection in effect, disabling... ");
- if (status & (1 << 7)) {
- msg_cdbg("Need to disable Sector Protection Register Lock\n");
- if ((status & (1 << 4)) == 0) {
- msg_cerr("WP# pin is active, disabling "
- "write protection is impossible.\n");
- return 1;
- }
- /* All bits except bit 7 (SPRL) are readonly. */
- result = spi_write_status_register(flash, status & ~(1 << 7));
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
-
- }
- /* Global unprotect. Make sure to mask SPRL as well. */
- result = spi_write_status_register(flash, status & ~0xbc);
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
- status = spi_read_status_register(flash);
- if ((status & (3 << 2)) != 0) {
- msg_cerr("Block protection could not be disabled!\n");
- return 1;
- }
- msg_cdbg("done.\n");
- return 0;
+ return spi_disable_blockprotect_generic(flash, 0x0C, 1 << 7, 1 << 4);
}
int spi_disable_blockprotect_at25df_sec(struct flashctx *flash)
@@ -470,72 +460,12 @@
int spi_disable_blockprotect_at25fs010(struct flashctx *flash)
{
- uint8_t status;
- int result;
-
- status = spi_read_status_register(flash);
- /* If block protection is disabled, stop here. */
- if ((status & 0x6c) == 0)
- return 0;
-
- msg_cdbg("Some block protection in effect, disabling... ");
- if (status & (1 << 7)) {
- msg_cdbg("Need to disable Status Register Write Protect\n");
- /* Clear bit 7 (WPEN). */
- result = spi_write_status_register(flash, status & ~(1 << 7));
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
- }
- /* Global unprotect. Make sure to mask WPEN as well. */
- result = spi_write_status_register(flash, status & ~0xec);
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
- status = spi_read_status_register(flash);
- if ((status & 0x6c) != 0) {
- msg_cerr("Block protection could not be disabled!\n");
- return 1;
- }
- msg_cdbg("done.\n");
- return 0;
-}
+ return spi_disable_blockprotect_generic(flash, 0x6C, 1 << 7, 0);
+ }
int spi_disable_blockprotect_at25fs040(struct flashctx *flash)
{
- uint8_t status;
- int result;
-
- status = spi_read_status_register(flash);
- /* If block protection is disabled, stop here. */
- if ((status & 0x7c) == 0)
- return 0;
-
- msg_cdbg("Some block protection in effect, disabling... ");
- if (status & (1 << 7)) {
- msg_cdbg("Need to disable Status Register Write Protect\n");
- /* Clear bit 7 (WPEN). */
- result = spi_write_status_register(flash, status & ~(1 << 7));
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
- }
- /* Global unprotect. Make sure to mask WPEN as well. */
- result = spi_write_status_register(flash, status & ~0xfc);
- if (result) {
- msg_cerr("spi_write_status_register failed.\n");
- return result;
- }
- status = spi_read_status_register(flash);
- if ((status & 0x7c) != 0) {
- msg_cerr("Block protection could not be disabled!\n");
- return 1;
- }
- msg_cdbg("done.\n");
- return 0;
+ return spi_disable_blockprotect_generic(flash, 0x7C, 1 << 7, 0);
}
/* === SST === */